1. Field of the Invention
This specification relates to a mobile terminal capable of controlling an operation of content displayed on a front surface according to a spaced distance between a laser detection auto focus (LDAF) sensor and a finger, and a method of controlling content thereof.
2. Background of the Invention
Terminals may be generally classified as mobile/portable terminals or stationary terminals. Mobile terminals may also be classified as handheld terminals or vehicle mounted terminals. Mobile terminals have become increasingly more functional. Examples of such functions include data and voice communications, capturing images and video via a camera, recording audio, playing music files via a speaker system, and displaying images and video on a display. Some mobile terminals include additional functionality which supports game playing, while other terminals are configured as multimedia players. More recently, mobile terminals have been configured to receive broadcast and multicast signals which permit viewing of content such as videos and television programs.
As it becomes multifunctional, a mobile terminal can be allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player. Efforts are ongoing to support and increase the functionality of mobile terminals. Such efforts include software and hardware improvements, as well as changes and improvements in the structural components.
In general, an auto focus (AF) function is used to capture a subject using a camera. The AF function essentially needs a distance measurement from the camera to the subject. The distance measurement from the subject may be performed by a method using infrared rays or supersonic waves and a through-the-lens (TTL) method.
The method of measuring a distance using ultrasonic waves is a method of calculating a distance by measuring a time that it takes for ultrasonic wave emitted from an ultrasonic wave generator of a mobile terminal to hit a subject and make its return. Further, the method of measuring infrared rays is a method of calculating a distance by measuring strength of infrared rays that returns after hitting a subject or a time that it takes for infrared ray to hit the subject and make its return.
The TTL method brings the camera into focus by analyzing an image obtained through a CCD/CMOS image sensor, and calculates a distance from a subject based on a location of a lens in the focused state. However, the method of measuring the distance using the infrared rays or ultrasonic waves is difficult to measure a distance up to a subject located at a far distance due to a limitation of a reachable distance of ultrasonic waves or infrared rays. Also, in this method, an accurate adjustment of focus on an object which is very close to a camera lens is hardly executed due to parallax.
Further, the TTL method can adjust the focus even on an object located at a far distance or an object very close to the camera lens, without any trouble. However, the CCD/CMOS image sensor cannot accurately detect contrast (details) of an object, such as an object (a blue sky, a monochromic wall, etc.) with a low contrast ratio, an object located at a place with less light, an object with high reflectivity, and the like, which results in a difficulty of distance measurement.
Therefore, a mobile terminal which measures a distance according to the related art method using the infrared rays or ultrasonic waves and the TTL method cannot measure an accurate distance, and thereby fails to perform an accurate AF function using those methods. Also, in the related art, the distance measurement technology is merely applied to a limited function, such as the auto focus, but fails to provide various functions and user interfaces (UIs) in association with an operation of content (or an application) output on a front display unit.